It is a fairly common procedure to utilize viable healthy blood vessels from one part of a patient's circulatory system as a graft in order to replace a blocked, damaged or diseased vessel at another location. For example, the coronary arteries are especially prone and subject to atherosclerosis as well as other vessel damaging and occluding diseases. Coronary bypass surgery commonly utilizes healthy segments of the radial artery, saphenous vein and other blood vessels as grafts to replace such diseased vessels.
In order to obtain a suitable length of a given artery or vein for use as a graft, a harvesting procedure in which a surgeon excises a desired length of donor vessel must first be accomplished. In accomplishing such harvesting procedures, the selected donor vessel must be safely separated from lateral (or branch) vessels arising from the main vessel to be harvested. Also, the donor vessel must be cleaved, at a proximal and distal point from them main vessel from which it arises in order to fully free the segment for use as a graft.
Harvesting procedures involve obtaining access to the donor vessel. In the past, such access has been accomplished with lengthy skin incisions made along the length of vessel to be harvested. Thereafter, blunt dissection of the vessel from connective tissue, fat and other structures adherent upon it, followed by cleavage of branch vessels was commonly performed. Recently, endoscopic approaches have been utilized to harvest vessels. Such procedures typically commence with small skin incisions made at locations in close proximity to the proximal and distal extent of the graft desired. Thereafter, an endoscope is utilized along with instruments, especially designed for endoscopic surgery, to accomplish blunt dissection and severing of the vessel from lateral branches. Such techniques are far more conservative in nature and involve substantially reduced skin incisions—and concomitant prolonged healing and pain—as compared to open techniques. However, the relatively small enclosed field in which multiple instruments must be utilized makes the procedure somewhat less than ideal. U.S. Pat. No. 5,899,912, Eaves III (the “'912 patent”) discloses a harvesting apparatus utilized in endoscopic removal of blood vessels. The disclosed harvesting instrument includes a harvesting head with a channel for receiving a blood vessel as well as at least one slot extending from the channel to the outer surface of the harvesting head for receipt of side branches of the vessel. The slot contains a blade for severing side branches and electro cautery for sealing the cut ends of the vessel. The outside surface of the harvesting head may be utilized for blunt dissection about the vessel to be harvested. Although the '912 patent discloses a harvesting instrument which provides blunt dissection as well as cleavage and sealing of side branches, the device does not provide any means of operator control or guidance of the position of vessels within the harvesting head save through the gross manipulation of a handle depending from the harvesting head. Also, no means is disclosed for retaining a vessel within the instrument during the cutting/cautery procedure.